We did a Cat trip week before last- flows definitely weren't all the way to the takeout at Dirty Devil, though they did last til around 7-10 miles from the takeout. We had a headwind to boot in the flatwater. I think it took us around 7 hrs to paddle from Imperial to the takeout, "roman-style" attaching our three rafts and dragging kayaks.
The new rapids were larger than we thought they'd be. There are four downstream of Imperial. Would've been more fun for me personally w/o the latenight antics and the 6 am wakeup call (I was a little more prepared for class II at that point)
Have a blast, take LOTS of water, and remember to regularly shotgun warm busch.